Class JSONObject
get
and opt
methods for
accessing the values by name, and put
methods for adding or
replacing values by name. The values can be any of these types:
Boolean
, JSONArray
, JSONObject
,
Number
, String
, or the JSONObject.NULL
object. A JSONObject constructor can be used to convert an external form
JSON text into an internal form whose values can be retrieved with the
get
and opt
methods, or to convert values into a
JSON text using the put
and toString
methods.
A get
method returns a value if one can be found, and throws an
exception if one cannot be found. An opt
method returns a
default value instead of throwing an exception, and so is useful for
obtaining optional values.
The generic get()
and opt()
methods return an
object, which you can cast or query for type. There are also typed
get
and opt
methods that do type checking and type
conversion for you.
The put
methods adds values to an object. For example,
myString = new JSONObject().put("JSON", "Hello, World!").toString();produces the string
{"JSON": "Hello, World"}
.
The texts produced by the toString
methods strictly conform to
the JSON syntax rules.
The constructors are more forgiving in the texts they will accept:
- An extra
,
(comma) may appear just before the closing brace. - Strings may be quoted with
'
(single quote). - Strings do not need to be quoted at all if they do not begin with a quote
or single quote, and if they do not contain leading or trailing spaces,
and if they do not contain any of these characters:
{ } [ ] / \ : , = ; #
and if they do not look like numbers and if they are not the reserved wordstrue
,false
, ornull
. - Keys can be followed by
=
or=>
as well as by:
. - Values can be followed by
;
(semicolon) as well as by,
(comma). - Numbers may have the
0-
(octal) or0x-
(hex) prefix. - Comments written in the slashshlash, slashstar, and hash conventions will be ignored.
-
Nested Class Summary
Modifier and TypeClassDescriptionprotected static final class
JSONObject.NULL is equivalent to the value that JavaScript calls null, whilst Java's null is equivalent to the value that JavaScript calls undefined. -
Field Summary
-
Constructor Summary
ConstructorDescriptionConstruct an empty JSONObject.JSONObject
(boolean sorted) Construct an empty sorted JSONObject.JSONObject
(Object bean) Construct a JSONObject from an Object using bean gettersJSONObject
(Object bean, boolean includeSuperClass) Construct JSONObject from the given bean.JSONObject
(Object object, String[] names) Construct a JSONObject from an Object, using reflection to find the public members.JSONObject
(String source) Construct a JSONObject from a source JSON text string.JSONObject
(String source, boolean sorted) Construct a JSONObject from a source JSON text string, optionally sorted.JSONObject
(Map<String, Object> map) Construct a JSONObject from a Map.JSONObject
(Map<String, Object> map, boolean includeSuperClass) Construct a JSONObject from a Map.JSONObject
(JSONObject jo, String[] names) Construct a JSONObject from a subset of another JSONObject.Construct a JSONObject from a JSONTokener.JSONObject
(JSONTokener x, boolean sorted) Construct a JSONObject from a JSONTokener, optionally sorted. -
Method Summary
Modifier and TypeMethodDescriptionaccumulate
(String key, Object value) Accumulate values under a key.Append values to the array under a key.static String
doubleToString
(double d) Produce a string from a double.Get the value object associated with a key.boolean
getBoolean
(String key) Get the boolean value associated with a key.double
Get the double value associated with a key.int
Get the int value associated with a key.getJSONArray
(String key) Get the JSONArray value associated with a key.getJSONObject
(String key) Get the JSONObject value associated with a key.long
Get the long value associated with a key.static String[]
Get an array of field names from an Object.static String[]
getNames
(JSONObject jo) Get an array of field names from a JSONObject.Get the string associated with a key.boolean
Determine if the JSONObject contains a specific key.boolean
Determine if the value associated with the key is null or if there is no value.keys()
Get an enumeration of the keys of the JSONObject.keySet()
Gets the set of keys.int
length()
Get the number of keys stored in the JSONObject.void
merge
(JSONObject jo, boolean overwrite, boolean deep) Merges the current JSON object with the given one, modifying the this.names()
Produce a JSONArray containing the names of the elements of this JSONObject.static String
Produce a string from a Number.Get an optional value associated with a key.boolean
optBoolean
(String key) Get an optional boolean associated with a key.boolean
optBoolean
(String key, boolean defaultValue) Get an optional boolean associated with a key.double
Get an optional double associated with a key, or NaN if there is no such key or if its value is not a number.double
Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a number.int
Get an optional int value associated with a key, or zero if there is no such key or if the value is not a number.int
Get an optional int value associated with a key, or the default if there is no such key or if the value is not a number.optJSONArray
(String key) Get an optional JSONArray associated with a key.optJSONObject
(String key) Get an optional JSONObject associated with a key.long
Get an optional long value associated with a key, or zero if there is no such key or if the value is not a number.long
Get an optional long value associated with a key, or the default if there is no such key or if the value is not a number.Get an optional string associated with a key.Get an optional string associated with a key.Put a key/boolean pair in the JSONObject.Put a key/double pair in the JSONObject.Put a key/int pair in the JSONObject.Put a key/long pair in the JSONObject.Put a key/value pair in the JSONObject.put
(String key, Collection<Object> value) Put a key/value pair in the JSONObject, where the value will be a JSONArray which is produced from a Collection.Put a key/value pair in the JSONObject, where the value will be a JSONObject which is produced from a Map.Put a key/value pair in the JSONObject, but only if the key and the value are both non-null.static String
Produce a string in double quotes with backslash sequences in all the right places.Remove a name and its value, if present.Get an enumeration of the keys of the JSONObject.toJSONArray
(JSONArray names) Produce a JSONArray containing the values of the members of this JSONObject.toString()
Make a JSON text of this JSONObject.toString
(int indentFactor) Make a pretty printed JSON text of this JSONObject.static String
valueToString
(Object value) Make a JSON text of an Object value.static String
valueToString
(Object value, int indentFactor, int indent) Make a pretty printed JSON text of an object value.Write the contents of the JSONObject as JSON text to a writer.
-
Field Details
-
NULL
It is sometimes more convenient and less ambiguous to have aNULL
object than to use Java'snull
value.JSONObject.NULL.equals(null)
returnstrue
.JSONObject.NULL.toString()
returns"null"
.
-
-
Constructor Details
-
JSONObject
public JSONObject()Construct an empty JSONObject. -
JSONObject
Construct an empty sorted JSONObject.- Parameters:
sorted
- true for sorted, false for none sorted
-
JSONObject
Construct a JSONObject from a subset of another JSONObject.An array of strings is used to identify the keys that should be copied. Missing keys are ignored.
- Parameters:
jo
- a JSONObjectnames
- an array of strings- Throws:
JSONException
- if a value is a non-finite number
-
JSONObject
Construct a JSONObject from a JSONTokener.- Parameters:
x
- a JSONTokener object containing the source string- Throws:
JSONException
- if there is a syntax error in the source string
-
JSONObject
Construct a JSONObject from a JSONTokener, optionally sorted.- Parameters:
x
- a JSONTokener object containing the source stringsorted
- true for sorted, false for none sorted- Throws:
JSONException
- if there is a syntax error in the source string
-
JSONObject
Construct a JSONObject from a Map.- Parameters:
map
- a map object that can be used to initialize the contents of the JSONObject
-
JSONObject
Construct a JSONObject from a Map.Note: Use this constructor when the map contains <key,bean>.
- Parameters:
map
- a map with Key-Bean dataincludeSuperClass
- tell whether to include the super class properties.
-
JSONObject
Construct a JSONObject from an Object using bean gettersIt reflects on all of the public methods of the object. For each of the methods with no parameters and a name starting with
"get"
or"is"
followed by an uppercase letter, the method is invoked, and a key and the value returned from the getter method are put into the new JSONObject.The key is formed by removing the
"get"
or"is"
prefix. If the second remaining character is not upper case, then the first character is converted to lower case.For example, if an object has a method named
"getName"
, and if the result of callingobject.getName()
is"Larry Fine"
, then the JSONObject will contain"name": "Larry Fine"
.- Parameters:
bean
- an object that has getter methods that should be used to make a JSONObject
-
JSONObject
Construct JSONObject from the given bean.This will also create JSONObject for all internal object (List, Map, Inner Objects) of the provided bean.
- Parameters:
bean
- an object that has getter methods that should be used to make a JSONObjectincludeSuperClass
- tell whether to include the super class properties.- See Also:
-
JSONObject
Construct a JSONObject from an Object, using reflection to find the public members.The resulting JSONObject's keys will be the strings from the names array, and the values will be the field values associated with those keys in the object. If a key is not found or not visible, then it will not be copied into the new JSONObject.
- Parameters:
object
- an object that has fields that should be used to make a JSONObjectnames
- an array of strings, the names of the fields to be obtained from the object
-
JSONObject
Construct a JSONObject from a source JSON text string.This is the most commonly used JSONObject constructor.
- Parameters:
source
- a string beginning with{
(left brace) and ending with}
(right brace)- Throws:
JSONException
- if there is a syntax error in the source string
-
JSONObject
Construct a JSONObject from a source JSON text string, optionally sorted.This is the most commonly used JSONObject constructor.
- Parameters:
source
- a string beginningsorted
- true for sorted, false for none sorted with{
(left brace) and ending with}
(right brace)- Throws:
JSONException
- if there is a syntax error in the source string
-
-
Method Details
-
doubleToString
Produce a string from a double. The string "null" will be returned if the number is not finite.- Parameters:
d
- a double- Returns:
- a String
-
getNames
Get an array of field names from a JSONObject.- Parameters:
jo
- the JSONObject- Returns:
- an array of field names, or null if there are no names
-
getNames
Get an array of field names from an Object.- Parameters:
object
- the object- Returns:
- an array of field names, or null if there are no names
-
numberToString
Produce a string from a Number.- Parameters:
n
- a Number- Returns:
- a String
- Throws:
JSONException
- if n is a non-finite number
-
quote
Produce a string in double quotes with backslash sequences in all the right places.A backslash will be inserted, allowing JSON text to be delivered in HTML. In JSON text, a string cannot contain a control character or an unescaped quote or backslash.
- Parameters:
string
- a String- Returns:
- a String correctly formatted for insertion in a JSON text
-
valueToString
Make a JSON text of an Object value.If the object has an value.toJSONString() method, then that method will be used to produce the JSON text. The method is required to produce a strictly conforming text. If the object does not contain a toJSONString method (which is the most common case), then a text will be produced by other means. If the value is an array or Collection, then a JSONArray will be made from it and its toJSONString method will be called. If the value is a MAP, then a JSONObject will be made from it and its toJSONString method will be called. Otherwise, the value's toString method will be called, and the result will be quoted.
Warning: This method assumes that the data structure is acyclical.
- Parameters:
value
- the value to be serialized- Returns:
- a printable, displayable, transmittable
representation of the object, beginning
with
{
(left brace) and ending with}
(right brace) - Throws:
JSONException
- if the value is or contains an invalid number
-
valueToString
Make a pretty printed JSON text of an object value.Warning: This method assumes that the data structure is acyclical.
- Parameters:
value
- the value to be serializedindentFactor
- the number of spaces to add to each level of indentationindent
- the indentation of the top level- Returns:
- a printable, displayable, transmittable
representation of the object, beginning
with
{
(left brace) and ending with}
(right brace) - Throws:
JSONException
- if the object contains an invalid number
-
accumulate
Accumulate values under a key.It is similar to the put method except that if there is already an object stored under the key then a JSONArray is stored under the key to hold all of the accumulated values. If there is already a JSONArray, then the new value is appended to it. In contrast, the put method replaces the previous value.
- Parameters:
key
- a key stringvalue
- an object to be accumulated under the key- Returns:
- this
- Throws:
JSONException
- if the value is an invalid number or if the key is null
-
append
Append values to the array under a key.If the key does not exist in the JSONObject, then the key is put in the JSONObject with its value being a JSONArray containing the value parameter. If the key was already associated with a JSONArray, then the value parameter is appended to it.
- Parameters:
key
- a key stringvalue
- an object to be accumulated under the key- Returns:
- this
- Throws:
JSONException
- if the key is null or if the current value associated with the key is not a JSONArray
-
get
Get the value object associated with a key.- Parameters:
key
- a key string- Returns:
- the object associated with the key
- Throws:
JSONException
- if the key is not found
-
getBoolean
Get the boolean value associated with a key.- Parameters:
key
- A key string- Returns:
- the truth
- Throws:
JSONException
- if the value is not a Boolean or the String "true" or "false"
-
getDouble
Get the double value associated with a key.- Parameters:
key
- a key string- Returns:
- the numeric value
- Throws:
JSONException
- if the key is not found or if the value is not a Number object and cannot be converted to a number
-
getInt
Get the int value associated with a key.If the number value is too large for an int, it will be clipped.
- Parameters:
key
- a key string- Returns:
- the integer value
- Throws:
JSONException
- if the key is not found or if the value cannot be converted to an integer
-
getJSONArray
Get the JSONArray value associated with a key.- Parameters:
key
- a key string- Returns:
- a JSONArray which is the value
- Throws:
JSONException
- if the key is not found or if the value is not a JSONArray
-
getJSONObject
Get the JSONObject value associated with a key.- Parameters:
key
- a key string- Returns:
- a JSONObject which is the value
- Throws:
JSONException
- if the key is not found or if the value is not a JSONObject
-
getLong
Get the long value associated with a key.If the number value is too long for a long, it will be clipped.
- Parameters:
key
- a key string- Returns:
- the long value.
- Throws:
JSONException
- if the key is not found or if the value cannot be converted to a long
-
getString
Get the string associated with a key.- Parameters:
key
- a key string- Returns:
- a string which is the value
- Throws:
JSONException
- if the key is not found
-
has
Determine if the JSONObject contains a specific key.- Parameters:
key
- a key string- Returns:
- true if the key exists in the JSONObject
-
isNull
Determine if the value associated with the key is null or if there is no value.- Parameters:
key
- a key string- Returns:
- true if there is no value associated with the key or if the value is the JSONObject.NULL object
-
keys
Get an enumeration of the keys of the JSONObject.- Returns:
- an iterator of the keys
-
keySet
Gets the set of keys.- Returns:
- the set of keys
-
length
Get the number of keys stored in the JSONObject.- Returns:
- The number of keys in the JSONObject
-
merge
Merges the current JSON object with the given one, modifying the this.- Parameters:
jo
- the JSON object to mergeoverwrite
- if to overwrite valuesdeep
- if to recurse in object values- Throws:
JSONException
- if a value is a non-finite number- Since:
- 7.6
-
names
Produce a JSONArray containing the names of the elements of this JSONObject.- Returns:
- a JSONArray containing the key strings, or null if the JSONObject is empty.
-
opt
Get an optional value associated with a key.- Parameters:
key
- a key string- Returns:
- an object which is the value, or null if there is no value
-
optBoolean
Get an optional boolean associated with a key.It returns false if there is no such key, or if the value is not Boolean.TRUE or the String "true".
- Parameters:
key
- a key string- Returns:
- the truth
-
optBoolean
Get an optional boolean associated with a key.It returns the defaultValue if there is no such key, or if it is not a Boolean or the String "true" or "false" (case insensitive).
- Parameters:
key
- a key stringdefaultValue
- the default- Returns:
- the truth
-
optDouble
Get an optional double associated with a key, or NaN if there is no such key or if its value is not a number.If the value is a string, an attempt will be made to evaluate it as a number.
- Parameters:
key
- a string which is the key- Returns:
- an object which is the value
-
optDouble
Get an optional double associated with a key, or the defaultValue if there is no such key or if its value is not a number.If the value is a string, an attempt will be made to evaluate it as a number.
- Parameters:
key
- a key stringdefaultValue
- the default- Returns:
- an object which is the value
-
optInt
Get an optional int value associated with a key, or zero if there is no such key or if the value is not a number.If the value is a string, an attempt will be made to evaluate it as a number.
- Parameters:
key
- a key string- Returns:
- an object which is the value
-
optInt
Get an optional int value associated with a key, or the default if there is no such key or if the value is not a number.If the value is a string, an attempt will be made to evaluate it as a number.
- Parameters:
key
- a key stringdefaultValue
- the default- Returns:
- an object which is the value
-
optJSONArray
Get an optional JSONArray associated with a key.It returns null if there is no such key, or if its value is not a JSONArray.
- Parameters:
key
- a key string- Returns:
- a JSONArray which is the value
-
optJSONObject
Get an optional JSONObject associated with a key.It returns null if there is no such key, or if its value is not a JSONObject.
- Parameters:
key
- a key string- Returns:
- a JSONObject which is the value
-
optLong
Get an optional long value associated with a key, or zero if there is no such key or if the value is not a number.If the value is a string, an attempt will be made to evaluate it as a number.
- Parameters:
key
- a key string- Returns:
- an object which is the value
-
optLong
Get an optional long value associated with a key, or the default if there is no such key or if the value is not a number.If the value is a string, an attempt will be made to evaluate it as a number.
- Parameters:
key
- a key stringdefaultValue
- the default- Returns:
- an object which is the value
-
optString
Get an optional string associated with a key.It returns an empty string if there is no such key. If the value is not a string and is not null, then it is coverted to a string.
- Parameters:
key
- a key string- Returns:
- a string which is the value
-
optString
Get an optional string associated with a key. It returns the defaultValue if there is no such key.- Parameters:
key
- a key stringdefaultValue
- the default- Returns:
- a string which is the value
-
put
Put a key/boolean pair in the JSONObject.- Parameters:
key
- a key stringvalue
- a boolean which is the value- Returns:
- this
- Throws:
JSONException
- if the key is null
-
put
Put a key/value pair in the JSONObject, where the value will be a JSONArray which is produced from a Collection.- Parameters:
key
- a key stringvalue
- a Collection value- Returns:
- this
- Throws:
JSONException
- if something goes wrong
-
put
Put a key/double pair in the JSONObject.- Parameters:
key
- a key stringvalue
- a double which is the value- Returns:
- this
- Throws:
JSONException
- if the key is null or if the number is invalid.
-
put
Put a key/int pair in the JSONObject.- Parameters:
key
- a key stringvalue
- an int which is the value- Returns:
- this
- Throws:
JSONException
- if the key is null
-
put
Put a key/long pair in the JSONObject.- Parameters:
key
- a key stringvalue
- a long which is the value- Returns:
- this
- Throws:
JSONException
- If the key is null
-
put
Put a key/value pair in the JSONObject, where the value will be a JSONObject which is produced from a Map.- Parameters:
key
- a key stringvalue
- a Map value- Returns:
- this
- Throws:
JSONException
- if something goes wrong
-
put
Put a key/value pair in the JSONObject.If the value is null, then the key will be removed from the JSONObject if it is present.
- Parameters:
key
- a key stringvalue
- an object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object- Returns:
- this
- Throws:
JSONException
- if the value is non-finite number or if the key is null.
-
putOpt
Put a key/value pair in the JSONObject, but only if the key and the value are both non-null.- Parameters:
key
- a key stringvalue
- an object which is the value. It should be of one of these types: Boolean, Double, Integer, JSONArray, JSONObject, Long, String, or the JSONObject.NULL object- Returns:
- this
- Throws:
JSONException
- if the value is a non-finite number.
-
remove
Remove a name and its value, if present.- Parameters:
key
- the name to be removed- Returns:
- the value that was associated with the name, or null if there was no value
-
sortedKeys
Get an enumeration of the keys of the JSONObject.The keys will be sorted alphabetically.
- Returns:
- an iterator of the keys
-
toJSONArray
Produce a JSONArray containing the values of the members of this JSONObject.- Parameters:
names
- a JSONArray containing a list of key strings. This determines the sequence of the values in the result- Returns:
- a JSONArray of values
- Throws:
JSONException
- if any of the values are non-finite numbers.
-
toString
Make a JSON text of this JSONObject.For compactness, no whitespace is added. If this would not result in a syntactically correct JSON text, then null will be returned instead.
Warning: This method assumes that the data structure is acyclical.
-
toString
Make a pretty printed JSON text of this JSONObject.Warning: This method assumes that the data structure is acyclical.
- Parameters:
indentFactor
- the number of spaces to add to each level of indentation- Returns:
- a printable, displayable, portable, transmittable
representation of the object, beginning
with
{
(left brace) and ending with}
(right brace) - Throws:
JSONException
- If the object contains an invalid number
-
write
Write the contents of the JSONObject as JSON text to a writer. For compactness, no whitespace is added.Warning: This method assumes that the data structure is acyclical.
- Parameters:
writer
- the writer to write the contents to- Returns:
- the writer
- Throws:
JSONException
- if something goes wrong
-